IPA: /ˈbɒtəm.ləs.li/
KK: /ˈbɑːtəmˌlɛsli/
In a way that has no limit or end; endlessly.
The ocean seemed to stretch bottomlessly into the horizon.
Bottomlessly → It is formed from "bottom" (from Old English "bōtm", meaning the lowest part or base) and the suffix "-less" (meaning without). The word "bottomlessly" means without a bottom or limit, suggesting an infinite depth.
Think of the 'lowest part' ('bottom') and remember that 'bottomlessly' means without any limit or depth.